Lime burning and kiln therefor



Mmm WM J. sm 9mm LUKE HURNlNG AND KLN THEREFOH 'mm April 29, 1940 .2 www5-@Sheet 1 WMW.. www. L simnmm LIME BURNING AND KILN THEREFOR Filad April 29, 19.40

72 Shams-Sheet Sig/f in un@ 2J formed in the roof le ci' euch kiln sud the ports I9 of the four kilns ill, Ei, i2 und iii sli cousily spaced and equi-distant from the common axis |4-I6.

Two lower ports ze are formed in the neck it) of each of the kilns. One of the ports 20 of the kiln l0 is connected by o conduit iii to u lower port 20 of the kiln ii end this conduit is controlled by dempers 22 and 22, the demper 2i? appertaining to the kiln i@ und the domper 28 to the kiln ii. Between the dempers 2S und iii? the conduit 2l is provided with en opening 28 leeding to atmosphere controlled hy e demper 2t?.

The other lower port 20 ci the il is similarly connected to o lower port of the kiln l2 by a conduit 3l controlled by dempers 3E und 33 and having an opening to etuosphere 3Q controlled by c damper 3S. '.ihe other lower port of the kiln l2 is connected to one ci the ports il@ of the kiln l@ by e conduit ii controlled icy damper-s l2 and it end loosing en opening to atmosphere $8 controlled hy e demper 6B.

Likewise the other port '26 oi the kiln itl is connected to the other port 25% of the l@ icy e conduit l controlled by dempers i522 and and having en opening to emaosphere 5ft controlled by s demper E5.

A ste-.ging i3d erected shove the buttery ci kilns supports an extractor fen @i the outlet of which is connected to a chimney 62. A due pipe it is connected to the inlet of the isn @i end the lower portion ci the flue pipe is concentric with the exis ift-iii end comprises e ioint @o with e. msnifold E5, liti' such thot the manifold is rotatable in relation to the due pipe titi shout the common exis ill-id.

The manifold comprises e due portion conm nected to the fixed due pipe st the joint dii and a bridging portion The rlue portion of the manifold has a downwerdly opening mouth lil adopted to resister with any one of the upper ports iti oi' the kilns i8, ii, it? end i3. The bridging portion ci? the uieniiold likewise has two downwardly opening mouths t@ end @il adapted to register with the upper ports itl of two adjacent when mouth is in register with e port of smother loins Each of the kilns is provided with e. cherging opening at the top havingr s detachable cover 'iii and with s discharging opening et the hose of the neck portion it normally closed icy u sliding shutter or like closure ineens li.

The battery of kilns may he o eieteo in c continuous regeneretive process in the following manner:

Assuming each kiln be charged with ruw limestone, chalk or shells upon which a loyer of solid fuel is superimposed sud the contents of the kiln itl to have been recently burnt. the lidlns it und i2 will be churged with raw lime and solid uel and the controlling devices oi the conduits corinected to the ports it and 2li are :adjusted into the position shown in Figures l und 2. In this position the bridging portion 6G of the manifold connects the upper port i9 oi the kiln lil to the upper port i9 of the kiln it and the :flue portion of the manifold connects the upper port it of the kiln i2 to the inlet of the ien it@ end thence tn the chimney @2.

The dempers 5E. 53, 32 and 33 are opened end all the other dempers ere closed. The fen t! will induce a, current of air through the opening d@ into the base of the kiln l@ through the lower port 20 thereof which is connected to the conduit di. The air will then pass up through the recently epesses burnt und hot contents of the kiln lil into the hrldsne portion @il of the manifold und thence through the upper port lil oi' the kiln i i During its psssuge through the kiln lil the air will be heated sufdciently to ignite the layer of solid fuel et the top of the kiln il (the contents of this kiln having been pre-heated as hereinafter described) Thence the eli* end products of combustion will pese in s, downward iiow to bum the raw materiel iu this kiln. On arriving at the base of the kiln il the gaseous stream will pass through the conduit il into the hase of the kiln i2 and up through the cherge therein which will thus be pre-heated end the gases will be cooled, thu-s reducing any tendency to ignite the layer of fuel et the top of this kiln. though the smount of air admitted through the opening 5d is preferably so regulated that the guess will. not be able to support combustion when they arrive at the kiln l2. From the top of the kiln i2 the gaseous stream posses through the flue portion il of the manifold and thence through the extractor fan 6i to the chimney GBE.

Whilst the contents o the kiln il are being burnt the kiln i3 is discharged and re-charged. When the burning oi' the lime in the kiln il is completed the manifold is turned clockwise into the position shown in Figure 3 so that its flue portion connects the upper port i9 of the kiln i3 to the chimney @i2 through the fan Si and its bridging portion 55 connects the upper ports i9 of the two kilns ii end i2.

The dempers t und e5 ere closed, the dempers 2d and 25 are opened, the dempers 32 and 33 are closed and the dempers 52 and S3 are opened. Air will now enter the conduit iii through the opening 2li, pass up through the recently burnt contents or the kiln ii to he pre-heated and to cool such contents, thence through the bridging portion C56 of the manifold. down through the kiln i2 to ignite the pre-heated loyer of fuel therein und to burn the pre-heated lime contents, the gaseous stream passing through the conduit (li into the bese of the kiln i3, up through the contents oi. that kiln to pre-heat its charge, the cooled gases finally passing through the flue portion G5 ci the manifold and the fen Gi to the chimney Meanwhile the cooled contents of the kiln i@ are being discharged and this kiln re-chsrged.

When the contents of the kiln i2 are completely burnt the manifold 55, @G is again turned clockwise for its mouths to register with the upper ports oi the kilns it, ifi and l2 und the dempers are manipulated to enable the contents oi' the kiln i3 to be humt in e. similar manner to that described above the process being repeated so that the contents of the various kilns are successively burnt.

Since the hot gases are forced to iow downwardly through the limestone which is being burnt, the equilibrium of iiow is stable across the cross-section. If a, locality tends to become over heated, the density of gases thereabout is reduced and the tendency is for the downward flow in that locality to be diminished und to be increased elsewhere. The diminished rate o iow in the overheated locality tends to cause a, reduction in tempeinture and thus there is en inherent tendency to preserve uniformity or" rate of flow over the whole cross-section.

In the result the limestone is more uniformly burnt throughout the volume or" the column and more precise regulation oi temperature end duration of treatment are rendered possible with Cil 

